Hair trimmer attachment



FIG. 1 is a right side elevational view of a hair trimmer attachment, showing my new design;

FIG. 2 is a front end elevational view thereof;

FIG. 3 is a rear end elevational view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a top plan view thereof; and

FIG. 6 is a left hand side elevational view thereof. 

The ornamental design for a hair trimmer attachment, as shown and described. 